Alpha Persei

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Alpha Persei

Not many stars have entire clusters named after them. One that does is Alpha Persei, the brightest star of Perseus, the hero. It’s a massive young star that’s nearing the end of its life. And it’s surrounded by a family of hundreds of other stars — the Alpha Persei Cluster.

Alpha Persei — also known as Mirfak — is the dominant member of the cluster. It’s at least eight times the mass of the Sun, about 70 times the Sun’s diameter, and 5,000 times the Sun’s brightness. That brilliance makes it easy to spot even though it’s more than 500 light-years away.

Several other big, bright stars are within a few light-years of Alpha Persei. And hundreds of smaller stars lie within a few dozen light-years. The stars are members of the cluster — a family of stars that was born from a single giant cloud of gas and dust.

Estimates of just when that took place vary, but the cluster’s maximum age appears to be about a hundred million years. At that age, Alpha Persei has already passed the end of its “normal” lifetime. Now, it’s about ready to expire. But just how it will do so isn’t clear. The star’s mass puts it near a dividing line. A star above that line explodes as a supernova. A star below the line dies a bit more quietly, leaving behind a small, hot ember known as a white dwarf.

Look for Alpha Persei in the northeast at nightfall. It’s far to the left of the Moon, and well above the brighter star Capella.

Script by Damond Benningfield

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